用电化学沉积法制备ZnO/Cu2O异质p-n结

由于P型ZnO的制备仍然存在一定的困难，限制了ZnO在光电方面的应用，尤其是在发光二极管和激光器的实际应用，目前利用P型的透明半导体氧化物与n型ZnO制备异质p-n结，成为新的研究热点。选择P型导电Cu2O与ZnO制备出异质p-n结。Cu2O是一种典型的P型半导体材料，禁带宽度为2．1eV，可见光范围的吸收系数较高。首次利用电化学沉积的方法制备了ZnO／Cu2O异质p-n结，研究了电沉积ZnO，Cu2O的生长机制和ZnO／Cu2O异质结的结构、光学和电学特性。

Electrodeposition of Cu2O/ZnO p-n Heterojunction

ZnO film is of great interest for short-wavelength optoelectronic application because ZnO semiconductor with a wide band gap of 3.34 eV has a large exciton binding energy of 60 meV at room temperature. However, there is almost no application based on the active function as a compound semiconductor. The primary reason is because most active functions in semiconductors come from the characteristic properties of p-n junction but the preparation of p-ZnO is in difficulty. There is of interest in the p-n heterojunction diode fabricated by using a combination of p-type oxide conductor and n-type ZnO. In this paper Cu_2O was chosen to compose p-n heterojunction with n-type ZnO. Cu_2O as a p-type direct-gap semiconductor with a bandgap energy of 2.1 eV, has been regarded as one of the most promising materials used for optoelectronic applications recently. Cu_2O is a potential photovoltaic material due to the low cost, non-toxicity and the natural abundance of the base material. Furthermore, Cu_2O is one of the few oxide semiconductors that are p-type. The nature of the p-type conductivity of Cu_2O is originated from the presence of Cu vacancies which form an acceptor level above the valence band. The heterojunction was prepared by two step cathodic electrodeposition. Electrodeposition is a simple and convenient method. It has several advantages also, such as low processing temperature, higher deposition rates, controllable film thickness and morphology. Uniform films can be formed on various substrates with complex shapes and employed with inexpensive equipments. The kinetics of electrodepostion of Cu_2O was discussed. X-ray diffraction, scanning electron microscopy, UV-Vis transmittance technologies were used to investigate the structural properties of the heterojunction. The electrical properties were also studied by measuring the I-V characteristic. The results showed that this simple electrochemical route was a favorable method to fabricate Cu_2O/ZnO heterojunciton.